QPHY-ENET Ethernet Serial Data Operator’s Manual Revision G – October, 2008 Relating to the Following Release Versions: • Software Option Rev. 5.7 • ENET Script Rev. 1.7 • Style Sheet Rev. 1.
LeCroy Corporation 700 Chestnut Ridge Road Chestnut Ridge, NY 10977–6499 Tel: (845) 578 6020, Fax: (845) 578 5985 Internet: www.lecroy.com © 2008 by LeCroy Corporation. All rights reserved. LeCroy, ActiveDSO, WaveLink, JitterTrack, WavePro, WaveMaster, WaveSurfer, WaveExpert, WaveRunner and WaveJet are registered trademarks of LeCroy Corporation. Other product or brand names are trademarks or requested trademarks of their respective holders. Information in this publication supersedes all earlier versions.
QPHY-ENET Software Option TABLE OF CONTENTS INTRODUCTION ........................................................................................................................ 7 Compatibility ............................................................................................................................................................... 7 10Base-T, 100Base-TX and 1000Base-T ..........................................................................................................
1000BT Template Tests section (D) ................................................................................................................. 69 Load & Probes section (F) ................................................................................................................................ 69 Differential Return Loss section (G)..................................................................................................................
QPHY-ENET Software Option Figure 33. 100Base-TX differential output voltage and overshoot ................................................................... 45 Figure 34. 100Base-TX Rise and Fall Time .......................................................................................................... 46 Figure 35. Transmitter test signal in IEEE 802.3-2005 standard in clause 40.6 ............................................... 47 Figure 36.
QPHY-ENET Operator’s Manual Rev G
QPHY-ENET Software Option INTRODUCTION QPHY-ENET is an automated test package that performs electrical tests for the three common networking standards over unshielded twisted pair (UTP) cables normally referred to as CAT5 or CAT5E. The electrical tests are performed on 10Base-T, 100Base-TX, and 1000Base-T signals as specified in the IEEE 802.3-2005 and ANSI X3.263-1995 standards. The QPHY-ENET option gives the user the ability to both automate compliance testing and debug devices, hosts and hubs.
Test Items 10Base-T [IEEE 802.3-2005] Peak Differential Output Voltage [14.3.1.2.1] Differential Output Voltage Harmonics [14.3.1.2.1] Template - Internal MAU (Normal & Inverted) [14.3.1.2.1] Template - External MAU (Normal & Inverted) [14.3.1.2.1] TP_IDL 100 Ω without TPM (Head & Tail) [14.3.1.2.1] TP_IDL Load 1 without TPM (Head & Tail) [14.3.1.2.1] TP_IDL Load 2 without TPM (Head & Tail) [14.3.1.2.1] Link Pulse 100 Ω without TPM (Head & Tail) [14.3.1.2.1] Link Pulse Load 1 without TPM (Head & Tail) [14.
QPHY-ENET Software Option Jitter Base to Lower [ANSI 9.1.9] Twisted Pair Active Output Interface template [ANSI Appendix J] 1000Base-T [IEEE 802.3-2005] on pair A, B, C and D Peak Differential Output Voltage point A, B, A vs. B, C, D [40.6.1.2.1] Maximum Output Droop FG, HJ [40.6.1.2.2] Template Mask point A, B, C, D, F, H [40.6.1.2.3] Transmitter Distortion - Mode 4 [40.6.1.2.4] Transmitter timing jitter Master (UnFiltered & Filtered) - Mode 2 [40.6.1.2.
TF-ENET-B Test Fixture Package The TF-ENET-B package is delivered in a soft pouch with a foam insert. TF-ENET-B Standard supplied items include: - Main Board - 50 Ω Terminator (6) - 6” RJ45 short cable (1) - Jumpers (28) - 18” SMA to SMA cables (2) - BNC to SMA adapters (2) Figure 1.
QPHY-ENET Software Option Ethernet Test Fixture Sections Figure 2.
TEST ITEM TF-ENET-B section A B C D E F G Jitter Test Cable Link Partner AWG 1000BASE-T X MODE 1, 4 with Disturber X X MODE 1, 4 without Disturber X MODE 2: MASTER JITTER with TX_TCLK X MODE 3: SLAVE JITTER with TX_TCLK X X X MODE 3: MASTER/SLAVE JITTER without TX_TCLK X COMMON MODE OUTPUT VOLTAGE 100BASE-TX UTP DIFFERENTIAL OUTPUT VOLTAGE X OVERSHOOT X SIGNAL AMPLITUDE SYMMETRY X RISETIME BASE TO UPPER X FALLTIME UPPER TO BASE X RISETIME LOWER TO BASE X FALLTIME BASE TO LO
QPHY-ENET Software Option QualiPHY Compliance Test Platform QualiPHY is LeCroy’s unique compliance test framework which leads the user through the compliance tests. QualiPHY displays connection diagrams to ensure tests run properly, automates the oscilloscope setup, and generates full compliance reports. QPHY-ENET (DSO option) can be used without QualiPHY if each compliance test is executed manually. However, QualiPHY makes QPHY-ENET easy and fast.
See the QualiPHY Operator’ s Manual for more information on how to use the QualiPHY framework. Figure 4.
QPHY-ENET Software Option INSTALLATION Oscilloscope Option Key Installation An option key must be purchased to enable the QPHY-ENET option. Call LeCroy Customer Support to place an order and receive the code. Enter the key and enable the purchased option as follows: 1. From the oscilloscope menu select Utilities Utilities SetupI 2. Select the Options tab and click the Add Key button. 3. Enter the Key Code using the on-screen keyboard. 4. Restart the oscilloscope to activate the option after installation.
QualiPHY tests the oscilloscope connection after clicking the Start button. The system prompts you if there is a connection problem. QualiPHY’s Scope Selector function can also be used to verify the connection. Please refer to the QualiPHY Operator’s Manual for explanations on how to use Scope Selector and other QualiPHY functions.
QPHY-ENET Software Option 5. Click the Configuration button in the QualiPHY main menu: 6. Select a configuration from the pop-up menu: Figure 6. QualiPHY configuration selection menu 7. Click Start. 8. Follow the pop-up window prompts.
Customizing QualiPHY The predefined configurations in the Configuration screen cannot be modified. However, you can create your own test configurations by copying one of the standard test configurations and making modifications. A description of the test is also shown in the description field when selected. Figure 7.
QPHY-ENET Software Option Once a custom configuration is defined, script variables and the test limits can be changed by using the Variable Setup and Limits Manager from the Edit/View Configuration window. Figure 8.
QualiPHY-ENET Operation After pressing Start in the QualiPHY menu, a pop-up connection diagram and dialog box is shown to help set up the test QualiPHY also instructs to change test signal mode (when necessary) with the QualiPHY pop-up message box shown as follows. Figure 9. Start button Figure 10. Example of pop-up message box Figure 11.
QPHY-ENET Software Option 1000Base-T A, B, C or D Pair Selection In the 1000Base-T test, a pop-up menu asks if the user is testing all 4 pairs of transmission lines. If selecting No, the user is then prompted for each pair individually. This allows the user to only test the selected pairs.
OSCILLOSCOPE OPERATION This topic explains how to operate the oscilloscope manually. All of the following steps explained are automated when using QualiPHY. Although the oscilloscope settings can be changed at any time, it is not recommended to do so while a QualiPHY script configuration is running. Doing so can modify the measurement and give erroneous report results. The main menu (pictured as follows) is shown at the bottom of the oscilloscope screen.
QPHY-ENET Software Option Source selection fields are displayed on the right side of the menu. The TF-ENET-B fixture is designed to use 2 SMA cables to ensure the best signal quality. The Differential Data on 2 Channels checkbox sets the oscilloscope to use two channels to probe the differential pair. Set C2 as Source for + Data and C3 as Source for - Data. Two controls for master TX_TCLK and slave TX_TCLK are used for the 1000Base-T mode 2 and mode 3 jitter tests, and are grayed out otherwise.
10Base-T Tests The required tests for the 10Base-T signal type are pulse mask, voltage level, and jitter. The requirements are given in the IEEE 802.3-2005 standard (clause 14). The mask test requires the use of a “Twisted Pair Model,” which effectively is a low-pass filter modeling the effect of transmitting the signal over a standard CAT5 cable. This Twisted Pair Model is available in section A of TF-ENET-B from LeCroy. Please refer to the test list in the 10 Base-T IEEE 802.3-2005 section of this manual.
QPHY-ENET Software Option 10Base-T DOV Mask and Voltage Test The differential output voltage (DOV) is defined as the absolute value of the peak differential voltage measured into a 100 Ω termination. The mask test evaluates the pulse shape. The transmitter should be set to generate a Pseudo Random bit pattern of at least 511 bits in duration. This type of pattern will repeat every 511 bits or more so that over a shorter measurement time, the data will appear to be random.
6. Click the Set Up and Start Test button to start the test and display the pass/fail results. 7. Repeat the mask test for each of the test loads (100 Ω, LOAD1, and LOAD2) by changing jumpers setting in Table 2, and for each pulse polarity (normal and inverted). There will be total 6 mask tests. Be sure to touch the Set Up and Start Test button after each test is selected. 8. Remove jumpers J1, J6, J14, J16, and install jumpers J7, J8, J9, J10, to test without TPM. 9.
QPHY-ENET Software Option Figure 16. DOV Peak Voltage Test Figure 17.
10Base-T TP_IDL Mask Test This test measures the wave shape of the TP_IDL signal at the output of the MAU. This signal is sent over the interface to indicate that the Device Under Test is ready to receive data. In this configuration, the TP_IDL signal is an end-of-packet indicator. The TP_IDL begins with a positive transition and must remain at a positive voltage level for between 2.5 and 4.5 bit times before going negative. Once the signal goes negative (below -50 mV) it may not exceed +50 mV.
QPHY-ENET Software Option 7. Select TP_IDL Tail Mask in the “Select Test” field. 8. Touch the Set Up and Start Test button to begin testing. 9. Install jumpers to test for TPM LOAD2; refer to Table 2 (previous). 10. Select TP_IDL Head Mask in the “Select Test” field. 11. Touch the Set Up and Start Test button to begin testing. 12. Select TP_IDL Tail Mask in the “Select Test” field. 13. Touch the Set Up and Start Test button to begin testing. 14.
Figure 20.
QPHY-ENET Software Option 10Base-T Link Test Pulse Mask The link test pulse is a single-bit positive-going pulse that is transmitted by the MAU whenever it is active, and before any traffic is present. This pulse is generated by a 10Base-T interface with no external connections. The link test pulse mask is similar to the TP_IDL mask except for its duration.
13. Install jumpers to test without TPM LOAD1. Refer to Table 2 (previous). X X 14. Select Link Test Pulse Head Mask in the “Select Test” field. 15. Touch the Set Up and Start Test button to begin testing. 16. Select Link Test Pulse Tail Mask in the “Select Test” field. 17. Touch the Set Up and Start Test button to begin testing. 18. Install jumpers to test without TPM LOAD2. Refer to Table 2 (previous). X X 19. Select Link Test Pulse Head Mask in the “Select Test” field. 20.
QPHY-ENET Software Option Figure 23.
10-Base-T Output Timing Jitter The timing jitter at the output of the MAU is determined by measuring the timing of the zero crossings at 8 bits and 8.5 bits from the triggering zero crossing. The jitter is measured and reported in parameter P1 below the grid on the oscilloscope display. A random bit stream from the device is used for this test, and two jitter measurements are made: one on the transition at 8 bits from the trigger and the other at the transition at 8.5 bits from the trigger.
QPHY-ENET Software Option 9. Select Output Timing Jitter 8.5 BT in the “Select Test Field.” 10. Select external or integrated MAU as appropriate in the “MAU Type” field. 11. Touch the Set Up and Start Test button to begin testing. 12. The measurement displayed in P1 is the peak-to-peak value of the variation in the location of the transition. 13. Install jumpers for the test without TPM 100 Ω. Refer to Table 2 (previous). X X 14. Select external or integrated MAU as appropriate in the “MAU Type” field.
Figure 26. Output Timing Jitter for 8.
QPHY-ENET Software Option 10Base-T Common Mode Output Voltage Test This test ensures that the zero to peak common mode output voltage at the MDI is within conformance limits. The zero to peak common mode output voltage is measured as the worst-case minimum to worst-case maximum common mode output voltage. This test does not use a high-pass filter. This measurement is made for pair A only. Figure 27. Fixture setup for Common Mode Output Voltage 1.
100Base-TX Tests The 100Base-TX signal is an MLT-3 signal, that is, symbols are encoded into one of three voltage levels on the twisted pair (+1, 0, and -1 V). The electrical requirements for this signal are defined in the ANSI X3.263-1995 standard for FDDI interfaces. The tests required by the standard are listed in the 100Base-TX [ANSI X3.2631995] section (previous). X X To run the full set of 100Base-TX tests, choose the 100BASE-TX All tests configuration in QualiPHY.
QPHY-ENET Software Option 100Base-TX compliance test patterns 100Base-TX testing requires special patterns that need to be generated from DUT port. DUT makers supply the software to generate these testing patterns. Figure 28. Fixture setup for 100Base-TX mask test 1. Connect the Device Under Test to the RJ45 jack J64 on the section G of TF-ENET-B using the short cable supplied in the fixture kit. 2.
been set in previous step. Figure 29. Adjustment of vertical scale and coupling The signal should be adjusted using the Volts/div control to fill the grid. Note the green checkmark in the Variable Gain control, which allows settings to be adjusted in 1 mV steps.
QPHY-ENET Software Option 100Base-TX Mask Test Mask testing of 100Base-TX signals is a useful and quick method to determine the signal quality. While the 802.3 and ANSI specifications do not strictly require it, it is commonly used because a compliant signal will not have any mask failures. More detailed analysis is required for compliance, however, because non-compliant signals may not exhibit mask failures. 1. Set the Device Under Test to transmit the IDLE 100Base-TX data pattern.
100Base-TX Jitter Test Jitter in 100Base-TX signals is defined as the time interval error between an ideal clock at the 125 MHz symbol rate and the measured timing of the rising and falling edges of the positive and negative pulses. The reference clock is recovered from the data signal under test using a numerical PLL computed from the threshold crossings of the signal under test. The jitter test is performed on a scrambled IDLE stream.
QPHY-ENET Software Option 100Base-TX Duty cycle distortion The duty cycle distortion measurement determines the timing error on four consecutive transitions of the transmitter signal, consisting of consecutive positive and negative pulses. This MLT-3 code is generated by a 10101010W sequence. Duty cycle distortion is measured as the maximum deviation from the nominal 16 ns spacing between all of the transitions at their 50% amplitudes. 1. Apply power to the Device Under Test.
100Base-TX Amplitude, Symmetry, and Overshoot The peak differential voltage of the MLT-3 signal should be +/-1 V, and the overshoot of transitions must be limited to 5 %. Additionally, the symmetry between the positive and negative pulses must be within 2 % of each other. The overshoot value is measured by capturing the peak voltage at a transition from 0 V to 1 V (or 0 V to -1 V) and comparing this level to the mean voltage of the signal when no transitions are occurring.
QPHY-ENET Software Option Figure 33.
100Base-TX Rise and Fall Time The rise time of the MLT-3 signal is defined as the transition time from the baseline (0 V) to either the positive or negative going peak, while the fall time is the time for the transition from either the positive or negative pulse to the baseline. The times are measured from the 10 to 90 % levels. They are also measured for all transitions in the waveform, and must be between 3 and 5 ns. In addition, all measured values for a given transmitter must be within 0.
QPHY-ENET Software Option 1000Base-T Measurements Transmitter measurements for gigabit Ethernet over copper (1000Base-T) are defined in the IEEE 802.3-2005 standard in clause 40.6. Four test modes are required in the physical layer device. A disturbing sine wave is required for modes 1 and 4. The frequency and amplitude of this sine wave for each mode is listed in Table 4 .
1000Base-T Peak Differential Voltage, Droop, Template - Mode 1 with Disturbing Signal This test is defined in 40.6.1.2.1 as: The absolute value of the peak of the waveform at point A and B, as defined in Figure 35 , shall fall within the range of 0.67V to 0.82 V (0.75 V +/-0.83 dB). These measurements are to be made for each pair while operating in test mode 1 and observing the differential signal output at the MDI using the transmitter test fixture with no intervening cable.
QPHY-ENET Software Option Figure 37. Block diagram of TF-ENET-B fixture section D 1. Calibrate data path (see the Signal Path Calibration Procedure topic on page 74 ). X X X X 2. Calibrate disturber sine wave (see the Disturber Calibration Procedure topic on page 77 ). X X X X 3. Connect AWG to J3 and J4. 4. Connect DUT to J68. 5. Install jumpers on J17/J19, J99/J100, J91/J92 and select Pair for your test.
10. The Average Result checkbox is checked by default. Entering a number in the Avg Weight field causes the selected number of waveforms to be averaged for each pulse (A, B, C, D, E and F). Note: The templates used in this test have a very tight tolerance so even a small amount of noise in the measurement setup can cause mask failures. It is recommended that averaging be used to reduce the measurement noise. The waveform looks distorted and may fail the mask while the averaging accumulates. 11.
QPHY-ENET Software Option Figure 39. 1000Base-T mode 1 test showing one mask; all mask test results are listed in the menu Figure 40.
1000Base-T Transmitter Distortion - Mode 4 with Disturbing Signal The distortion test measures the error in the signal under test relative to an ideal waveform generated by a mathematical model of the PAM-5 coded signal. TF-ENET-B section D, which contains the disturbing signal, is used for this test. The disturbing signal is set to a frequency of 20.833 MHz (125 MHz / 6) at a peak-to-peak amplitude of 2.7 V at the input to the DUT. This is set using the Fixture Calibration procedure.
QPHY-ENET Software Option Figure 41. Setting the disturbing signal level for mode 1 test Figure 42.
Mode 1 and Mode 4 without Disturbing Signal These tests are performed on a physical interface transmitting the mode 1 and mode 4 waveform. Test section G is used to perform the peak voltage and template tests. When a disturbing signal is not used, the measurement should be made with the device terminated by a 100 Ω resistive load.
QPHY-ENET Software Option 2. Use Differential Return Loss section of the board (G: recommended), for SMA cable connection (differential probe can be used for section F). 3. Alternately, use the 1000BT template section as follows. Install jumpers on J77/J71 (the oscilloscope connects to the DUT input signal) and install jumpers according to Table 7 : X Pair A B C D Install J39, J40 J43, J44 J41, J42 J45, J46 X Remove J61, J60, J62 J59, J60, J62 J59, J61, J62 J59, J61, J60 Table 7.
Figure 45. Mode 2 and Mode 3 w/o TX_TCLK w/o Link Partner Figure 46.
QPHY-ENET Software Option 1000Base-T Master Jitter - Mode 2 without TX_TCLK Clause 40.6.1.2.5 of IEEE 802.3-2005 says to measure the jitter between the TX_TCLK and the data at the MDI (Medium Dependent Interface) that is Jtxout - apply a 5 kHz high-pass filter to the TX_TCLK jitter, measure the peak-to-peak remaining jitter, and add Jtxout, the result must be less than 0.3 ns. Also, the result of measuring the peak-to-peak jitter on the TX_TCLK relative to an un-jittered reference must be less than 1.4 ns.
1000Base-T Slave Jitter - Mode 3 without TX_TCLK Note : The following test must only be done after the Mode 2 without clock test (previous) is done on each pair. This is because the two results from the Mode 2 without clock test are remembered and used for this one. Approximating the slave jitter tests with only the MDI port available is harder than approximating the master jitter tests.
QPHY-ENET Software Option 1000Base-T Master and Slave Jitter - with TX_TCLK For devices exposing TX_TCLK, as required by 802.3-2005, jitter can be measured as specified in the 802.32005 standard. This process involves three steps. 1. Measure Jtxout, defined as the peak-to-peak jitter on the MDI output signal (data) relative to the TX_TCLK, while the DUT is in test mode 2 (Master timing mode) or test mode 3 (Slave timing mode).
8. Repeat this process for each of the four MDI pairs in both the master timing mode (test mode 2) and the slave timing mode (test mode 3). The menu item labeled “Master TX_TCLK” is always named this way and should be used as such for test modes 2 and 3. When all 8 values have been measured, enter the worst Master Jtxout and the worst Slave Jtxout values on the oscilloscope, on the “Jtxout values” tab of the Ethernet Tests dialog. These values will be used in steps 2 and 3. Figure 47.
QPHY-ENET Software Option Step 2: Master TX_TCLK Jitter This step measures both unfiltered and filtered TX_TCLK jitter in Master mode. Note: This measurement requires access to the master TX_TCLK signal. This clock can be probed on one of the pins of the PHY chip using an active probe. Contact your PHY chip vendor for information on the location of this signal. 1. Attach an active or differential probe (Minimum Bandwidth 1.5GHz) to the TX_TCLK signal to the DUT.
Step 3: Slave TX_TCLK Jitter Jitter in slave mode is designed to measure the jitter in the recovered clock in the Device Under Test relative to the reference clock in a second 1000Base-T transmitter (also known as the Link Partner in this test). The Link Partner is connected to the Device Under Test using a section of specially-configured CAT5 cable as described in IEEE 802.3-2005 in clause 40.6.1.1.1. The test channel description from the specification is reproduced in figure 52 (as follows).
QPHY-ENET Software Option Figure 50. Example Slave with TX_TCLK Jitter display. The trace shows the filtered track of the timing jitter between the master and slave clock signals (TX_TCLK).
1. Set the Device Under Test for normal operation in Slave mode. 2. Use an active or differential probe (Minimum Bandwidth 1.5GHz) to probe the TX_TCLK on the Device Under Test (slave). 3. Connect a second active or differential probe (Minimum Bandwidth 1.5GHz) to the TX_TCLK on the Link Partner (master). 4. On the oscilloscope’s Ethernet Menu, enter which channels are connected to which signals. 5. Ensure that the DUT is receiving valid data by verifying the DUT GMII management register bit 10.
QPHY-ENET Software Option Figure 51.
1000Base-T Common Mode Output Voltage Test This test ensures that the peak-to-peak common mode output voltage at the MDI is within conformance limits. The peak-to-peak common mode output voltage is measured as the worst-case minimum to worst-case maximum common mode output voltage. This test does not use a high-pass filter. This measurement is made for 4 pairs (A,B,C,D) by changing J35, J36, J37, J38 jumper pins. Figure 52. Fixture setup for Common Mode Output Voltage 1.
QPHY-ENET Software Option TF-ENET-B JUMPER PIN CONFIGURATION GENERAL INFORMATION This section provides a quick reference to TF-ENET-B test fixture along with the LeCroy QPHY-ENET Ethernet compliance test software. Figure 53. TF-ENET-B test fixture board Figure 54.
Jumpers and Connectors Section A: With TPM; J1/J6/J14/J16, Without TPM; J7/J8/J9/J10, 100 Ω:J24/J25, Load1: J20/J21, Load2: J22/J23, Link Partner termination: J98. Section B: Pair A; J15/J58, B; J18/J66, C; J56/J69, D; J57/J70 Section C: Pair A; J35, B; J36, C; J37, D; J38. Signal termination when using differential probe: J55.
QPHY-ENET Software Option As shown on the board, J15 and J58 connect pair A to the oscilloscope; J18 and J66 connect pair B to the oscilloscope; J56 and J69 connect pair C to the oscilloscope and J57 and J70 connect pair D to the oscilloscope. Install jumpers only on one of these pairs. Common Mode Output Voltage section (C) In this section, each side of an Ethernet signal pair is connected to a common point through a 47.5 Ω resistor.
LINK PARTNER TESTING FOR 10BASE-T & 100BASE-TX DEVICES Note: Link Partner testing is for informational purposes only. The required compliant test patterns are not available in Link Partner Mode. The second RJ45 connector (J27) in the 10BT w & w/o TPM section is used for link partner testing for both 10Base-T and 100Base-TX Devices. Remove jumper J98 to use the link partner’s termination of pair A. Figure 55.
QPHY-ENET Software Option The DUT should be providing data output instead of just the link pulse. When this occurs, the DUT is ready to be tested. Note: When performing 10Base-T testing with a link partner, the signal output from the previous procedure is used for all tests except the Link Test Pulse Head and Tail Tests. Be sure to disconnect the link partner from the test fixture for these tests.
TF-ENET-B TEST AND CALIBRATION PROCEDURES This topic describes the procedures to calibrate the TF-ENET-B connection cables and signal path and the Disturbing Signal for 1000Base-T Mode 1 and Mode 4 tests. Cable Deskewing The following procedure demonstrates how to deskew two oscilloscope channels and cables using the differential data signal of the DUT - with no need for any T connector or adapters. This can be done once the temperature of the oscilloscope is stable.
QPHY-ENET Software Option In the previous procedure, we used the default setup of the Skew parameter (which is detecting positive edges on both signals at 50%). We also inverted C3 in order to make C2 and C3 both have positive edges at the same time. Alternately, we clearly could have not inverted C3 and instead selected the Skew clock 2 tab in the P1 parameter menu and set the oscilloscope to look for negative edges on the second input (C3).
Signal Path Calibration Procedure Even the highest quality differential probes will be non-linear and have noise levels that may be unacceptable for measuring 1000Base-T Ethernet signals. The noise and distortion in the probe will add to the signal being measured and may result in mask or distortion failures. One way to eliminate probing effects is to connect the signal under test directly to the oscilloscope inputs.
QPHY-ENET Software Option 1. Connect DUT to J68. 2. Install jumpers on J71 and J77, and remove jumpers from J91, J92, J99 and J100. 3. Connect the oscilloscope channel 2 to J86, channel 3 to J87. The 50 Ω termination of the oscilloscope inputs will terminate the signal pair with 100 Ω. J91, J92 connect oscilloscope to output of the power divider. J77, J71 connect oscilloscope to input signal pair. J17 and J19 connect the output of the splitters to J3 and J4.
Figure 60. Data Amplitude measurement for Splitter calibration 6. Connect AWG to J3 and J4. 7. Set AWG output to 0 V. 8. Remove jumpers from J71, J77, and install jumpers on J17, J19, J91, J92, J99 and J100. 9. On the Fixture Calibration dialog, press Measure (Attenuated Data), wait for it to finish. 10. Press Apply to apply the calibration settings. Figure 61. Attenuated data measurement for Splitter calibration Note: The TF-ENET-B fixture attenuation is close to 3.00 dB.
QPHY-ENET Software Option Disturber Calibration Procedure This procedure measures the amplitude of the disturbing sine wave being applied to the DUT. The calibration is required to adjust the amplitude of the disturbing sine wave, which is generated by a dual-channel waveform generator with 180-degree phase shift. See Table 4. Gigabit Ethernet tests, modes and fixtures for the various signal frequency and amplitude settings used throughout the tests.
Disturbing Signal Source The signal generator used as the disturbing signal source must be set as follows. The exact amplitude of the signal depends on the result from the calibration. See the Disturber Calibration Procedure (previous). X X Mode 1 Disturbing Signal CH1 : Waveform: SINE, Frequency: 31.25 MHz, Phase 0 degree CH2 : Waveform: SINE, Frequency: 31.25 MHz, Phase 180 degree Mode 4 Disturbing Signal CH1 : Waveform: SINE, Frequency: 20.833 MHz, Phase 0 degree CH2 : Waveform: SINE, Frequency: 20.
